Lets look at that quote again shall we?
I used my iPhone and the Red Laser app to scan all the toys my kids wanted. It shows all the prices for the stores around me, as well as online.
(emphasis mine)
If you can't wrap your head around the fact that any person who has already set foot in your store is a potential sale, you'd make a terrible salesperson. Checking prices is not a guarantee that the customer is going to shop somewhere else. If your prices are even in the same ballpark, there is a decent chance they'll pick up the item *now* because they are already there, and it is convenient. If the staff was pleasant, that is another point in their favor.
The entire issue here is that some sales geek at Toys'r'us made an *assumption* that someone checking prices on their phone will definitely not make any purchases while they are in the store. By making that assumption, they probably swayed that customer away from making any purchases, and in fact, they have now generated negative word of mouth. Harassing shoppers is a pretty terrible way to move product. I work for one of those "big" B&M stores, and if I saw a sales associate harassing a customer for checking prices on their phone, they'd be in the office for a quick refresher on the benefits of friendliness.
Frankly, taking your money to another business, be it online or another retailer, is never unethical. No one has any obligation to keep a store in business just because they happened to walk in and take up their floorspace for a few minutes. The store is responsible for their own survival, and part of that is balancing operating costs against actual sales. Plenty of retailers are surviving just fine in the face of online (and mail-order before that) competition so far, the ability to check prices real-time instead of ahead of time is *not* going to push a currently profitable retailer over the edge now. Smart retailers are looking for ways to utilize their customer's smart phones, instead of waving their hands in panic that now they can get real-time pricing data.